Fracture mechanics of propagating 3-D fatigue cracks with parametric dislocations

Akiyuki Takahashi, Nasr M. Ghoniem

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Propagation of 3-D fatigue cracks is analyzed using a discrete dislocation representation of the crack opening displacement. Three dimensional cracks are represented with Volterra dislocation loops in equilibrium with the applied external load. The stress intensity factor (SIF) is calculated using the Peach-Koehler (PK) force acting on the crack tip dislocation loop. Loading mode decomposition of the SIF is achieved by selection of Burgers vector components to correspond to each fracture mode in the PK force calculations. The interaction between 3-D cracks and free surfaces is taken into account through application of the superposition principle. A boundary integral solution of an elasticity problem in a finite domain is superposed onto the elastic field solution of the discrete dislocation method in an infinite medium. The numerical accuracy of the SIF is ascertained by comparison with known analytical solution of a 3-D crack problem in pure mode I, and for mixed-mode loading. Finally, fatigue crack growth simulations are performed with the Paris law, showing that 3-D cracks do not propagate in a self-similar shape, but they re-configure as a result of their interaction with external boundaries. A specific numerical example of fatigue crack growth is presented to demonstrate the utility of the developed method for studies of 3-D crack growth during fatigue.

Original languageEnglish
Pages (from-to)2662-2679
Number of pages18
JournalPhilosophical Magazine
Volume93
Issue number20
DOIs
Publication statusPublished - 1 Jul 2013

Keywords

  • crack growth
  • cracks
  • dislocation dynamics
  • dislocations
  • fatigue
  • fracture mechanics

Fingerprint

Dive into the research topics of 'Fracture mechanics of propagating 3-D fatigue cracks with parametric dislocations'. Together they form a unique fingerprint.

Cite this